Disc sander

ABSTRACT

A disc sander includes a rotary disc on which an abrasive paper is adhered for grinding workpieces. The abrasive paper is replaced by dismantling and replacing a new rotary disc adhered with a new abrasive paper without the need of peeling off the to-be-replaced abrasive paper. The disc sander includes a guard, which is moveable between a sheltered position where the guard covers around a periphery of the rotary disc to ensure the user&#39;s safety, and an unsheltered position where the rotary disc is not covered by the guard and accessible by the user, such that the user can conveniently dismantle the rotary disc from an output shaft of a motor and then install a new rotary disc, on which an abrasive paper having required roughness is adhered, on the output shaft.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates generally to machine tools, and more particularly, to a disc sander having an improved structure.

2. Description of the Related Art

As shown in Taiwan Patent Publication No. 419341, a conventional disc sander, which utilizes a motor as a power source to drive an abrasive disc to grind workpieces, is generally composed of an inclination adjustable worktable arranged outside an axial end of a circular rotary disc, facilitating user to put workpiece on the worktable to enable that the workpiece can be ground by an abrasive paper adhered on the disc surface of the rotary disc. Such type of conventional disc sander has been being used extensively for many years though it has sort of disadvantage to be improved.

In actual use, various abrasive papers of different roughness may be required to fulfill the grinding requirements of different workpieces in a grinding task. To replace the abrasive paper of the above-mentioned conventional disc sander, the used abrasive paper must be peeled off from the rotary disc and then a new, desired abrasive paper is adhered to the rotary disc. This replacement work is not only complicated and inconvenient but also liable to cause damage or broke of the used abrasive paper due to the grounds that the used abrasive paper adhered on the rotary disc has insufficient structural strength to sustain the peeling force exerting thereon, resulting in that the used abrasive paper may not be reusable after it is peeled off, causing waste.

SUMMARY OF THE INVENTION

The present invention has been accomplished in view of the above-noted circumstances. It is an objective of the present invention to provide an improved disc sander, which can be conveniently replaced with a new rotary disc adhered with desired abrasive paper to fulfil the need of replacing abrasive paper so as to avoid the work of peeling off the used abrasive paper from the rotary disc.

To attain the above objective, the present invention provides a disc sander comprising a rotary disc for being adhered with an abrasive paper for grinding workpieces, which can be dismantled, such that the effect of changing abrasive paper can be achieved by replacing the rotary disc without the need of peeling off the abrasive paper. To this end, a primary technical feature of the present invention lies in that a guard used in the disc sander for covering the rotary disc to ensure working safety can easily alter its guarding status to the rotary disc. When the guard does not cover around the rotary disc, i.e. the barrier of the guard to the rotary disc is removed, the user can conveniently dismantle the rotary disc from an output shaft of a motor serving as a driving power source, and then install a new rotary disc, on which an abrasive paper having required roughness is adhered, on the output shaft, thereby achieving the above objective and effect.

In technical speaking, a disc sander provided by the present invention comprises a base, a worktable disposed on the base, a motor disposed on the base and provided with an output shaft adjacent to a lateral side of the worktable, a rotary disc between the worktable and the motor, and a guard capable of covering a periphery of the rotary disc. The guard is moveably coupled to the base and moveable between a sheltered position and an unsheltered position. When the guard is located at the sheltered position, the guard covers an outside of a periphery of an upper half of the rotary disc, such that the guard forms a safety shelter around the periphery of the upper half of the rotary disc. When the guard is located at the unsheltered position, the guard does not cover the outside of the periphery of the upper half of the rotary disc, such that the periphery of the rotary disc is accessible without being sheltered.

The technical way that the guard is moveably coupled to the base may be a completely or partially separated coupling way. For example, a first end of the guard may be pivotally coupled to the base, such that the guard is reciprocatingly swivelable about a pivot center formed by a pivot joint of the guard between the sheltered position and the unsheltered position.

To enhance the user's convenience of installing or dismantling the rotary disc, the disc sander of the present invention is further configured in a way that the relative spatial positions between the motor carrying the rotary disc and the base are adjustable.

To enhance operational convenience, the disc sander of present invention may be configured that the base comprises two lateral members spaced from each other, and a mount pivotally connected between the two lateral members. The worktable is mounted on the lateral members and the motor is mounted on the mount. By means of changing the position of the mount relative to the lateral members, the position of the motor and the position of the rotary disc that is coupled to the output shaft of the motor are adjusted, thereby achieving the effect of convenient operation.

Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description given herein below and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:

FIG. 1 is a front and left side perspective view of a disc sander in accordance with a preferred embodiment of the present invention;

FIG. 2 is a rear and left side perspective view of the disc sander in accordance with the preferred embodiment of the present invention;

FIG. 3 is an exploded view of the disc sander in accordance with the preferred embodiment of the present invention;

FIG. 4 is a front view of the disc sander in accordance with the preferred embodiment of the present invention, showing that a guard is located at a sheltered position;

FIG. 5 is another front view of the disc sander, showing that the guard is located at an unsheltered position;

FIG. 6 is a left side view of the disc sander in accordance with the preferred embodiment of the present invention, showing that a mount is located at an upright position; and

FIG. 7 is another left side view of the disc sander, showing that the mount is located at an inclined position.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1-3, a disc sander 10 provided by a preferred embodiment of the present invention mainly comprises a base 20, a worktable 30, a motor 40, a rotary disc 50, a guard 60, and a coupling unit 70.

The base 30 includes a plate-like bottom portion 21 and a support portion 22 fixedly mounted on the bottom portion 21. As such, the bottom portion 21 serves as a foundation and the support portion 22 forms a support structure for being installed with the worktable 30 and the motor 40 at an appropriate height above the bottom portion 21. The worktable 30 and the motor are installed on the support portion 22.

The support portion 22 includes two parallel plate-like lateral members 221 disposed on the two lateral edges of the bottom portion 21, respectively. Each lateral member 221 is provided at a top side thereof with a flange 2211 extending horizontally by bending. The horizontal flange 2211 has one or more strip-like through sliding holes 2212. The support portion 22 further includes a mount 222 having two lateral sides each pivotally connected with an end part 2213 of the top side of one of the lateral members 221, such that the mount 222 is swivelable about a pivot shaft 224 formed by the pivot joint between the mount 222 and the lateral members 221 between an upright position and an inclined position. When the mount 222 is located at the upright position as shown in FIG. 6, an installation surface 2221 at a lateral side of the mount 222 is parallel to a plumb line (gravity line). When the mount 222 is located at the inclined position as shown in FIG. 7, an included angle is formed between the installation surface 2221 of the mount 222 and the plumb line.

For positioning the mount 222 at the upright position, the support portion 22 further includes two elongated rods 225 and two compression springs 226 sleeved onto the elongated rods 225, respectively. By means of the spring forces of the compression springs 226, the mount 222 can be resiliently maintained at the upright position. Each rod 225 has an end laterally and pivotally connected with one of the lateral members 221, and the other end slidably inserted through the mount 222 in a way that an end of each compression spring 226 is abutted against the mount 222 and the other end of each compression spring 226 is restricted by a relatively big diameter portion provided at the end of the rod 225.

In another aspect, for positioning the mount 222 at the inclined position, the support portion 22 further includes two arc positioning holes 227 respectively provided at and penetrating through the lateral members 221 and aimed at each other, and two positioning handle levers 228 having shafts inserted respectively through the positioning holes 227 for imparting positioning forces at appropriate portions of the positioning holes 227 so as to position the mount 222 at an inclined posture of a specific angle. The positioning handle lever 228 in the present invention is same in structure as a conventional quick-release handle lever; therefore, the positioning handle lever 228 is well known by a person skilled in the art and won't be necessarily described in detail hereunder.

The worktable 30 is placed across the flanges 2211 of the lateral members 221 and fixedly mounted to the top side of the lateral members 221 by fastening members, such as screws, inserting through the sliding holes 2212. As such, a lateral side of the worktable 30 is adjacent to the mount 222.

The motor 40 is a well-known electric device, which is fixedly mounted on the installation surface 2221 of the mount 222, such that the position of the motor 40 relative to the lateral members 221 can be changed along with the swivel motion of the mount 222. The motor 40 has an output shaft 41 penetrating through the mount 222 and located at a height close to an imaginary horizontal plane at which the worktable 30 is situated.

The rotary disc 50 is fixedly coupled to the output shaft 41 of the motor 40 and located between the output shaft 41 and the worktable 30 in a way that a lateral disc surface of the rotary disc 50 is adjacent to the lateral side of the worktable 30. The lateral disc surface is adapted for being adhered with an abrasive paper of predetermined roughness, such that when the motor 40 drives the rotary disc 50 to rotate, the abrasive paper can grind a contact portion of a workpiece placed on worktable 30.

The guard 60 is moveably coupled to the mount 222 of the support portion 22 and moveable between a sheltered position and an unsheltered position. When the guard 60 is located at the sheltered position as shown in FIG. 4, the guard 60 covers the part of the rotary disc 50 high above the worktable 30, namely the upper half of the rotary disc that is located above the imaginary horizontal plane at which the worktable 30 is situated. As such, the guard 60 forms a safety shelter around the periphery of the upper half of the rotary disc 50 to ensure the user's safety. When the guard 60 is located at the unsheltered position as shown in FIG. 5, the guard 60 does not cover the outside of the periphery of the upper half of the rotary disc 50, such that the rotary disc 50 and the set screw (not shown) for fastening the rotary disc 50 to the output shaft 41 can be directly and freely accessible by the user without any barrier.

Detailedly speaking, the guard 60 includes an arc end plate 61, a back plate 62 mounted to a lateral side of the end plate 61, a front plate 64 mounted to the other lateral side of the end plate 61, and a pivot piece 63 mounted to the back plate 62 and attached on the installation surface 2221 in a way that an external pivot member (not shown), such as a pivot shaft, is inserted through the pivot piece 63 and the mount 222. As a result, the guard 60 is pivotally connected at a first end thereof with the mount 222 in a way that the guard 60 is reciprocatingly swivelable about the pivot shaft provided between the guard 60 and the mount 222 of the support portion 22 between the sheltered position and the unsheltered position. Further, in the preferred embodiment, the pivot shaft extends in a direction orthogonal to an imaginary plane at which the rotary disc 50 is situated in a way that the extending direction of the pivot shaft does not pass through the rotary disc 50.

The coupling unit 70 is adapted for positioning the guard 60 at the sheltered position, which may include a first coupling member and a second coupling member structurally engageable with each other. The first and second coupling members are respectively disposed on the guard 60 and the mount 222, such that when the guard 60 is located at the sheltered position, the guard 60 can be locked at the sheltered position by means of engagement of the first coupling member with the second coupling member, thereby ensuring user's safety in operation. Specifically, the first coupling member is a protrusion 71 having a notch, which is disposed on an end of the back plate 62, namely a second end of the guard 60, remote from the pivot piece 63. The second coupling member is a well-known quick-release handle lever 72, which is disposed on the mount 222 at a place corresponding to the protrusion 71 at the sheltered position. As a result, when the guard 60 is located at the sheltered position, the shaft of the quick-release handle lever 72 is engaged with the notch of the protrusion 71 such that the guard 60 can be locked at the sheltered position by means of the locking function of the quick-release handle lever 72.

With the above-mentioned technical features, to replace the abrasive paper, the user needs not to peel off the abrasive paper as the prior art does. The user only needs to stop the disc sander 10, move the guard 60 to the unsheltered position, loosen and remove the set screw engaged between the rotary disc 50 and the output shaft 41, remove the used rotary disc 50 from the output shaft 41, and then install a new rotary disc, on which an abrasive paper of desired roughness is already adhered, on the output shaft 41, thereby completing the replacement work of abrasive paper. In this way, the complicated procedure of peeling off the used abrasive paper can be avoided and the used abrasive paper can be reused.

In another aspect, in the process of replacing the rotary disc, to provide sufficient space to the user for convenient operation, the user can not only move the worktable 30 along the sliding holes 2212 in an allowable sliding range of the sliding holes 2212 to increase the distance between the rotary disc 50 and the worktable 30 but also set the mount 222 at an inclined posture of a proper angle. In this way, even if the set screw between the rotary disc 50 and the output shaft 41 is removed, the rotary disc 50 can still be hung on the output shaft 41 due to the gravity so as to prevent the rotary disc 50 from unexpected falling from the output shaft 41, thereby enhancing the user's safety in the replacement work.

The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims. 

What is claimed is:
 1. A disc sander, comprising: a base having a bottom portion and a support portion uprightly disposed on the bottom portion; a worktable disposed on the support portion; a motor disposed on the support portion and provided with an output shaft adjacent to a lateral side of the worktable; a rotary disc between the worktable and the motor, the rotary disc being fixedly mounted to the output shaft and provided with a lateral disc surface adjacent to the lateral side of the worktable in a way that an upper half of the rotary disc is located above an imaginary plane at which the worktable is situated; a guard disposed on the support portion and extending along a periphery of the rotary disc and covering an outside of the periphery of the rotary disc; wherein the guard is moveably coupled to the support portion and moveable between a sheltered position and an unsheltered position; when the guard is located at the sheltered position, the guard covers an outside of a periphery of the upper half of the rotary disc, such that the guard forms a safety shelter around the periphery of the upper half of the rotary disc; when the guard is located at the unsheltered position, the guard does not cover the outside of the periphery of the upper half of the rotary disc, such that the periphery of the rotary disc is accessible without being sheltered.
 2. The disc sander as claimed in claim 1, wherein the guard includes a first end pivotally coupled to the support portion, such that the guard is reciprocatingly swivelable about a pivot shaft provided between the guard and the support portion between the sheltered position and the unsheltered position.
 3. The disc sander as claimed in claim 2, wherein the pivot shaft extends in a direction orthogonal to an imaginary plane at which the rotary disc is situated in a way that the direction does not pass through the rotary disc.
 4. The disc sander as claimed in claim 2, further comprising a coupling unit disposed with the guard and the support portion for coupling the guard to the support portion.
 5. The disc sander as claimed in claim 4, wherein the coupling unit comprises a first coupling member disposed on a second end of the guard, a second coupling member disposed on the support portion; when the guard is located at the sheltered position, the first coupling member and the second coupling member are engaged with each other; when the guard is located at the unsheltered position, the first coupling member is departed away from the second coupling member.
 6. The disc sander as claimed in claim 5, wherein the second coupling member is a quick-release handle lever having a shaft, and the first coupling member is a protrusion having a notch; when the guard is located at the sheltered position, the shaft of the quick-release handle lever is engaged with the notch of the protrusion.
 7. The disc sander as claimed in claim 1, wherein the guard comprises an end plate located outside the periphery of the rotary disc, and a front plate located outside the lateral disc surface of the rotary disc and fixed to the end plate.
 8. The disc sander as claimed in claim 1, wherein the support portion comprises two lateral members spaced from each other, and a mount pivotally connected between the two lateral members and swivelable between an upright position and an inclined position.
 9. The disc sander as claimed in claim 8, wherein the worktable is mounted on the two lateral members, and the motor is mounted on the mount.
 10. The disc sander as claimed in claim 8, wherein the support portion comprises an elongated rod having an end coupled to one of the two lateral members, and the other end slidably inserted through the mount; a compression spring is sleeved onto the elongated rod; the compression spring has an end abutted against the mount for imparting a spring force on the mount to maintain the mount at the upright position. 